Dislocation-mediated strain hardening in tungsten: Thermo-mechanical plasticity theory and experimental validation

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  • Peking University

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Abstract

A self-consistentthermo-mechanicalmodeltostudythestrain-hardeningbehaviorof polycrystallinetungstenwasdevelopedandvalidatedbyadedicatedexperimentalroute. Dislocation–dislocationmultiplicationandstorage,aswelldislocation-grainboundary (GB)pinningwerethemajormechanismsunderlyingtheevolutionofplasticdeformation, thus providingalinkbetweenthestrainhardeningbehaviorandmaterial'smicro- structure.Themicrostructureofthepolycrystallinetungstensampleshasbeenthoroughly investigatedbyscanningandelectronmicroscopy.Themodelwasappliedtocompute stress–strain loadingcurvesofcommercialtungstengrades,intheas-receivedandas- annealedstates,inthetemperaturerangeof500–1000 °C. Fittingthemodeltothein- dependentexperimentalresultsobtainedusingasinglecrystalandas-receivedpoly-crystalline tungsten,themodeldemonstrateditscapabilitytopredictthedeformation behavior ofas-annealedsamplesinawidetemperaturerangeandappliedstrain.The relevanceofthedislocation-mediatedplasticitymechanismsusedinthemodelhavebeen validatedusingtransmissionelectronmicroscopyexaminationofthesamplesdeformed up todifferentamountsofstrain.Onthebasisoftheexperimentalvalidation,thelim- itationsofthemodelaredeterminedanddiscussed.

Details

Original languageEnglish
Pages (from-to)1-15
Number of pages15
JournalJournal of the Mechanics and Physics of Solids
Volume85
DOIs
Publication statusPublished - 28 Aug 2015

Keywords

  • Tungsten, Crystal plasticity, Hardening, Dislocations

ID: 3368226